Hi guys,
My microwave oven broke down last month.
Not only it's a pain in the backside but it is also more waste for the planet.
A quick search on the internet educated me about safety and how to test parts.
Turns out the main board is dead (display works fine, most buttons too but "start" and "stop" buttons are useless).
New motherboard is difficult to source and is no more available from manufacturer (i bought it 2 years ago but must have been some fairly old design... :face_with_rolling_eyes: )
So back to drawing board and soldering iron:
- arduino nano
- 2.8" TFT colour display
- rotary encoder
- salvage "power board" from microwave (gives 12V and 5V)
I am pretty well on my way design-wise and need a final advice on transistors ; following are 2 arrangements regarding what i would call the "oven door transistor" (the bottom PNP one).
The 3 NPN transistors at the top drive a relay each one (magnetron, plate and heating resistance). Each transistor is driven by the arduino via a resistor.
Please accept my apologies if any of my sketches make your eyes bleed. :grin:
Which one would be the least bad and how could it be improved.
Thanks a lot for reading :+1:
EDIT: Sketches drawn with https://www.falstad.com

